municipal wastewater efficiency improvements potential savings for the 6 th power plan september 30,...
TRANSCRIPT
Municipal Wastewater Efficiency Improvements
Potential Savings for the 6th Power Plan
September 30, 2008Regional Technical Forum
South Treatment Plant - Renton,Washington
Municipal Wastewater Industry in the PNW• Over 800 Plants use 175 aMW of Energy• Processes Include
– Collection– Treatment
• Sludge Processing & Disposal
– Discharge
Picture from: Arkansas Watershed Advisory Group
The Many Factors that Affect Plant Energy Consumption
• Influent Biological Oxygen Demand (BOD)• Effluent BOD• Weather/Location• MGD design capacity • MGD flow• Primary Clarifier Effectiveness• Secondary Treatment Process Type
– Activated Sludge• Coarse or fine bubble aeration• Dissolved Oxygen control method
– Aerated Lagoon• Dispersed Aeration or Mechanical Aeration• Varying amounts of aeration
– Trickle Filter– Disinfection method (Chlorine or UV)
• Tertiary Treatment Process Type• Sludge Treatment Processes
– Dewatering method– Digestion
• Onsite Generation (IC Engine or Micro-Turbine Using Digester Gas, Micro-Hydro at discharge, etc.)
Lebanon, OR
Energy Savings Measures• Energy Savings Measures
– VFDs – Upgrade to premium efficiency motors– Aeration blower control via automated dissolved oxygen monitoring– Fine bubble diffusers– Optimize pumping and blower configurations and operation/controls– Upgrade to more efficient pumps and blowers– Use hydraulic digester mixing & optimize mixing time– Lighting
DO Control from wateronline.com
Blower from spenserturbine.com
Fine Bubble Diffusters from sequencertech.com
5th Power Plan Summary• Technical Potential
Retrofit Measures = 50.5 aMW New Construction = 14.5 aMW
65.0 aMW
• Plan called for a total of 37 aMW of energy savings at 1.4 cents/kWh.
Achievements since 5th Plan• Energy Trust of Oregon:
– 23 Projects– Savings = 1.5 aMW– Measure Cost = $10 million
Update for 6th Plan: Data SourcesVariable Source(s) DataNumber of Plants in PNW, by type
5th Plan Assumptions2001 Quantum survey of facilities in PNW, and facility type
Growth Council Population ProjectionsNeeds met assuming 50% increased plant utilization and 50% increased capacity
Plant Utilization 2004 EPA Clean Watersheds Needs Survey Average Flow and Design Capacity for PNW Facilities
5th Plan AssumptionsAggregated results of BacGen/Quantum Survey of 194 Facilities in PNW and CA
Phone calls to 9 Large Plants in PNW (represent over 40% of the capacity in Large PNW plants)
Design and Average flow, energy consumption, and generation
PG&E Benchmarking Study Design and Average flow, and energy use of 9 plants
2008 "Importance of EE to W&WW Sector" paper by M. Yonkin
Energy Use per treated water by plant size
PNW BacGen Projects through 2003 (n=17) Energy Use (and flow)
5th Plan AssumptionsEnergy savings per flow, through conversations with Industry
2006 NYSERDA Sub Metering Study 11 submetered sites
PNW BacGen Projects through 2003 (n=17) Energy Savings (and flow)
Long Term Monitoring and Tracking Report on 2006 Activities: BacGen (Summit Blue, 2007)
Energy Savings (and design capacity) from 33 facilities
2006 NYSERDA Sub Metering Program Detailed measure cost for 11 sites
ETO - Ted Light Total measure cost for 23 facilities
O&M Costs & Savings 2006 NYSERDA Sub Metering Program Detailed O&M benefits (and costs) for 11 sites
Achieved Energy Savings ETO - Ted Light Total energy savings and number of sites
Measure Cost
Baseline Energy Consumption
Energy Savings Potential
Proposed Changes to Savings
5th Plan Assumptions (2005)Million
kWh/MGD (flow)
Plant Utilization
Number of Plants
Total Capacity
(MGD)Total Annual Flow (MGD)
Total Energy Consumption
(aMW)
Energy Savings
Potential
Savings (million kWh per MGD
flow)Energy Savings
Potential (aMW)< 1 MGD 1.347 75% 276 96 72 11 30% 0.40 31 to 10 MGD 1.347 75% 114 396 297 46 25% 0.34 11> 10 MGD 1.347 75% 49 1,612 1,209 186 9% 0.16 22
1.439 75% 121 319 239 39 30% 0.43 121.131 75% 281 153 115 15 25% 0.28 4
842 2,575 1,932 297 53Proposed 6th Plan Assumptions (2010)
Million kWh/MGD
(flow)Plant
UtilizationNumber of Plants
Total Capacity
(MGD)Total Annual Flow (MGD)
Total Energy Consumption
(aMW)
Energy Savings
Potential
Savings (million kWh per MGD
flow)Energy Savings
Potential (aMW)< 1 MGD 1.347 70% 289 100 70 11 30% 0.40 31 to 10 MGD 1.347 67% 119 414 275 42 12% 0.16 5> 10 MGD 0.493 74% 51 1,684 1,239 70 9% 0.04 6
1.439 67% 127 333 222 36 30% 0.43 111.131 70% 294 160 112 14 25% 0.28 4
880 2,691 1,918 174 29
Lagoon Extended AerationLagoon Aerated/Mixed
Activated Sludge
Lagoon Extended AerationLagoon Aerated/Mixed
Activated Sludge
Treatment Type
Treatment Type
More on Savings
Data Source NSavings (million kWh/MGD flow)
< 1 MGD 3 0.591 to 10 MGD 3 0.14> 10 MGD 3 0.05< 1 MGD 9 0.691 to 20 MGD 23 0.16> 20 MGD 1 0.04
NYSERDA Submetering (activated sludge)
BacGen Projects (all plant types) (assumes 67% plant utilization rate)
Change large activated sludge plant baseline consumption because:
Change % savings available to medium activated sludge plants because:
Proposed Changes to Cost & Benefits
5th Plan AssumptionsMeasure Cost per
kWh SavedO&M & NEB per
kWh Saved B/C Ratio< 1 MGD 0.19$ 0.30$ 4.91 to 10 MGD 0.06$ 0.07$ 8.4> 10 MGD 0.07$ 0.27$ 31.0
0.09$ 0.09$ 7.90.43$ 0.33$ 4.0
Proposed 6th Plan Assumptions (2010)Measure Cost per
kWh SavedO&M & NEB per
kWh Saved B/C Ratio< 1 MGD 1.10$ 0.10$ 1.41 to 10 MGD 0.49$ 0.10$ 3.2> 10 MGD 0.48$ 0.03$ 2.2
0.49$ 0.10$ 3.21.10$ 0.10$ 1.4
Activated Sludge
Lagoon Extended AerationLagoon Aerated/Mixed
Treatment Type
Activated Sludge
Lagoon Extended AerationLagoon Aerated/Mixed
Treatment Type
Data Source NMeasure Cost per
kWh SavedO&M & NEB
per kWh Saved< 1 MGD 3 $1.10 $0.101 to 10 MGD 3 $0.49 $0.10> 10 MGD 3 $0.48 $0.00
23 $0.73 ?
NYSERDA Submetering
ETO Projects5th Plan Assumptions:• Measure Cost:
– $20k to $200k depending on size (or about $0.10/kWh)
• O&M Costs:– $500/mo service agreement
• Non Energy Benefits:– $34k/year per facility for
reduced manual DO sampling– $5/day for reduced polymer
purchased in AS systems– $10k-25k/MGD for reduction
in solids